A full-color liquid crystal display device (TFT-LCD) installed in a monitor system for a vehicle includes a liquid crystal display (LCD), an LCD electronic control unit (ECU). The LCD has a backlight unit that includes white LEDs and red LEDs. The LCD ECU performs a display control process for selectively displaying navigation information, a tachometer image, or other information. A warning sign is displayed in a single color red in a display area of the LCD if required. The LCD ECU selects information to display and determines whether the information is a warning. If the information is a warning, the white LEDs and the red LEDs are turned on for displaying a warning sign indicative of the warning at high intensity so that the sign is easily recognized. If the information is not a warning, only the white LEDs are turned on.